In DE 10 2006 002 812 A1, a generic device and a corresponding method are described. In a spinning preparation machine, in particular a card, carding machine, or the like, in which a clothed fast-rotating roller is arranged opposite to at least one clothed and/or non-clothed component and the spacing between the opposing components is changeable, it is provided for monitoring and/or adjusting of spacings at the components that the components are electrically insulated with respect to each other. As respective contact elements, these components are connected to an electrical circuit in which a measuring element for contact detection is integrated. The clothed fast-rotating roller is, for example, a card cylinder, wherein the opposing clothed and/or non-clothed component are/is, for example, a doffer roller, a flat or a casing segment that has a guiding surface. Between the roller and the component arranged spaced apart therefrom, there is the so-called carding gap. This carding gap is very narrow and can change during the operation due to the components heating up. This can result in contacts between the fast-rotating roller and the opposing component. Such contacts are to be avoided whenever possible.
Accordingly, DE 10 2006 002 812 A1 proposes to avoid undesirable frequent contact between the components and therefore to avoid damage to the clothing by determining the number of contacts, as a result of which an indication or reaction in the case of only one of these contacts or only a few contacts is avoided. In particular, an undesirable shutdown of the machine is avoided in this manner. In order to achieve this, an evaluation of the number of contacts of a certain contact duration, e.g., a contact duration of 0.1 ms, 1 ms or 2 ms is filtered. For this purpose, a counting device is provided which determines the number of contacts per time unit between a card clothing and a clothing strip. This number or amount of contacts is used for further evaluation and for the reaction resulting therefrom, for example, for stopping the card or for continued operation of the card.
A disadvantage of this solution is that each individual tooth of the clothing generates an individual contact with the opposing component and therefore increases the number of contacts. The technical implementation of this proposal is very complicated. In particular, for a component that is arranged opposite to the clothed card cylinder and is also provided with a clothing, it is necessary to monitor each individual clothing needle in terms of its potential so as to be able to detect the number of contacts. Apart from that, determining the number or amount of contacts would not be possible since a short contact with this clothing-covered component would already indicate a single contact in the same manner as it would indicate continuous contacting of both components across a plurality of clothing tips. This very inaccurate or else very complicated determination of the number of contacts is hardly implementable in practice.